JPS6390688A - Screw compressor - Google Patents

Abstract

PURPOSE:To improve sealing property between a front end of a male rotor and the inner surface of a cylinder chamber by making the maximum radius of the male rotor smaller by slight amount than the radius of the cylinder chamber while forming an arcuate portion having this radius throughout a predetermined angle on an end of a lobe of the male rotor. CONSTITUTION:A lobe 204 of a male rotor 202 is formed on the pointed end with an arcuate portion A110-11 extending over a predetermined angle. The radius of the arcuate portion A1 is set to the radius R smaller by a slight amount than the inside radius R0 of a second cylinder chamber 102 housing the male rotor 202. On the other hand,a female rotor 201 meshing with the male rotor 02 is formed with a cycloid curve portions 31-36 generated by an end 10 of the arcuate portion A1. The end of lobe 204 of the male rotor 202 makes surface contact with the inner peripheral surface of second cylinder chamber 102 through a fine gap to improve substantially the sealing property.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a screw compressor, and is effective for use as a refrigerant compressor in, for example, an automobile air conditioner.

[Conventional technology and its problems]

2. Description of the Related Art Screw compressors that compress refrigerant by meshing a male rotor and a female rotor have been known. Moreover, various methods are known for appropriately setting the shapes of the male rotor and female rotor in such a screw compressor. For example, the tooth profile is formed from a continuously curved curve with a short contact line (Japanese Patent Publication No. 19979/1979); Publication No. 45-20061 and the final publication), conversely, a tooth profile with small blowholes rather than continuity with the length of the contact line, (Special Publication No. 51
-43604) and one in which the tooth profile shape takes into consideration the thermal expansion of the rotor during actual operation (Japanese Patent Application Laid-Open No. 59-598)
8189) and the like are known.

However, in the tooth profile design concept of conventional screw compressors, no consideration has been given to the sealing performance in the seal line formed between the rotor tooth tip and the cylinder chamber of the housing.

[Problem that the invention seeks to solve]

The present invention was devised in view of the above-mentioned points, and an object of the present invention is to form a seal portion on every rotor tooth tip to prevent leakage at the rotor tooth tip.

[Configuration and operation]

In order to achieve the above object, in the compressor of the present invention, a male rotor is rotatably housed in a cylinder space having a radius R0. Then, the maximum outer diameter of this male rotor is determined by the cylinder chamber radius R0.
The radius R is made slightly smaller. And 2. A A circular arc portion having radius R is formed at the tip of the protruding portion of the rotor over a predetermined angle. - On the other hand, a female rotor that meshes with the male rotor is also rotatably disposed within the cylinder chamber, and the concave portion of this female rotor has a cycloid curve created by the above-mentioned circular arc portion of the male rotor. Form a curved part.

With the above configuration, the male rotor and the female rotor can smoothly interact with each other at the pressure 1iia of the present invention, and the rotation of one rotor is reliably transmitted to the other rotor. Furthermore, an arcuate portion is formed at the tip of the protrusion of the male rotor over a predetermined angle, and this arcuate portion allows the tips of the teeth of the male rotor to come into surface contact with the inner surface of the cylinder chamber.

As a result, the sealing performance between the tip of the male rotor and the inner surface of the cylinder chamber is greatly improved, and compressed fluid does not leak through the tip of the male rotor teeth.

〔Effect of the invention〕

As explained above, the compressor of the present invention has the excellent effect of significantly improving the sealing performance at the tooth tips of the rotor and improving the compression performance of the compressor.

〔Example〕

Hereinafter, one embodiment of the compressor of the present invention will be described based on the drawings. In FIG. 1, 300 is a housing made of aluminum alloy, and as shown in FIG. 2, there is a cylindrical first cylinder 10 inside.
It has first and second cylinders 102. This housing 300 is closed at both ends by a front side plate 354 and a rear side plate 355. Bearings 320 to 324 are disposed on each of the plates 354 and 355, and the male rotor 202 and the female rotor 201 are slidably disposed by these bearings 320 to 324. The chick rotor 201 is formed integrally with a shaft 352, and the shaft 352 is connected to the front housing 3.
It is exposed outwardly from the tip 351 of 30 and rotates by receiving the rotational driving force of the automobile engine through an electromagnetic clutch (not shown).

A shaft sealing device 331 is disposed in the front housing 330, and this shaft sealing device 331 prevents lubricating oil and refrigerant inside the compressor from leaking outward along the shaft 352.

A suction communication hole (not shown) is formed in the front housing 330, and a low-temperature, low-pressure refrigerant is sucked into the suction chamber 356 from the evaporator of the refrigeration cycle. Suction chamber 356
are in communication with suction passages 386 and 387 formed in the front side plate 354, and in communication with suction holes 357 and 358 formed in the housing 300.

That is, the compression chamber 500 formed by the female rotor 201 and the female rotor 202 and the cylinder chambers 101 and 102 can be opened to the suction holes 357 and 358 of the housing 300. Refrigerant is sucked into the compression chamber 500 through the suction holes 357 and 358, and as the volume of the compression chamber decreases, the sucked refrigerant is compressed. A discharge hole is opened at the position where the volume of the compression chamber is reduced the most, and compressed gas is discharged into the discharge chamber 363 in the case 390 through this discharge hole. This discharge chamber communicates with a condenser of the refrigeration cycle via a discharge communication passage (not shown). Note that a seal plate 362 is provided at the end of the rear side plate 355, and the high pressure in the discharge chamber 363 is transferred to the bearing 321,
324 and the rotors 201, 202 directly.

Next, the tooth profile shapes of the male rotor 202 and the female rotor 201 will be explained based on FIG. 3. The male rotor has a protrusion 20
4 are formed at four locations equally spaced apart in the circumferential direction. Furthermore, six concave grooves 205 are formed on the female rotor 201 at equal intervals in the circumferential direction. Since each of the protrusions 204 and the grooves 205 have the same shape, the shape of one of them will be explained with reference to FIG. 3. In the male rotor 202 of this example, the protrusion 204 has an arcuate portion A at its tip. Hereinafter, the shape of each point of the rotor will be designated by the point number shown in FIG. That is, the arc portion A is 10-1
It is 1. The radius of this arc portion 10-11 is R, and this radius R is slightly smaller than the inner diameter R0 of the second cylinder chamber 102 by 1t (20 to 40 μ). Further, the angle α of the arc portions 10-11 is about 5 degrees. A circular arc shaped portion 11-12 is formed adjacent to the circular arc portion 10-11. The radius R0 of this arcuate portion 11-12 is smaller than the radius R described above. Next, female rotor 2
Curve section 12- created by curve section 32-33 of 01
13 is molded. Furthermore, a curved portion 13-14 is formed continuously from this curved portion 12-13. This curved portion 13-
14 is a curve created by the curved portions 33-34 of the female rotor 201. Furthermore, curve 13-14! This continuous arc 14-15 is formed. This arc 14-15 is a tangent to the pitch circle of the curve 13-14. This tangent line 14
-15 is continuous with curve 15-16 at point 15. This curve 15-16 is the point 3 of the female rotor 201.
This is a curve created by 5.

Curves 10 to 17 from point IO of the above-mentioned arc portion A1
are continuous. This curve 10-17 is the curve created by point 36 of the female rotor.

Moreover, this curve 10-17 is the straight line 36 of the female rotor 201.
Continuing to the curve 17-18 created by -37. Curve 17-18 is continuous at point 1 with a straight line 4i 18-19 towards center 7, which line 18-19 is continuous at point 19 with curve 19-20 created by point 38 of female rotor 201. The tooth profile of the protrusion 204 of the male rotor 202 is determined by the above-mentioned curve and straight line.

On the other hand, the tooth profile of the concave portion 205 of the female rotor 201 is determined as follows. The arc 31-32 is the male rotor 2 mentioned above.
The radius r is almost the same as the arc 11-12 of 02. It becomes more.

Also, continuous to this arc 31-32, the center is point 9
A circular arc 32-33 with radius R5 is formed. arc 3
3 is continuous with straight line 33-34. This straight line 33-
34 is a straight line that touches radius r at point 33 and has an angle of β at point 34. Note that β is 20'.

The straight line 33-34 is then the straight line 14-1 of the male rotor 202.
5 created by Salel's music vA34-35.

Further, on the point 31 side of the above-mentioned circular arc portion 31-32, the cycloid curve 31-36 created by the point 10 of the male rotor 202 continues. This cycloid song vA
31-36 are then continuous with a straight line 36-37 towards the center point 6 of the first cylinder chamber 101. Also, straight line 36-3
7 is continuous with the straight line 37° 38 created by the straight line vA18, 19 of the male rotor 202.

Note that the maximum outer diameter of the female rotor 201 is the same as that of the first cylinder chamber 1.
The radius R1 is a very small amount (approximately 20 to 40 μm smaller than the radius R1 of 01. In addition, the straight line 4.5 in FIG. 3 is the pitch circle of the male rotor 202 and the female rotor 201, respectively.

Next, the operation of the compressor having the above configuration will be explained. The rotational force of an automobile engine (not shown) is transmitted to the shaft 352.
If the signal is transmitted to the female rotor 201 via the female rotor 20
1 rotates within the housing 300. Here, since the projection 204 of the rotor 202 is engaged with the groove 205 of the female rotor, the rotation of the female rotor 201 is received.
Male rotor 202 also rotates within housing 300 at the same time.

With this rotation, the compression chamber 500 repeatedly increases and decreases its volume.

A suction hole 357.3 is provided at a position where the compression chamber 500 increases in volume.
58 is open, and the refrigerant in the suction chamber 356 is sucked into the compression chamber 500 through the suction holes 357 and 358.

Next, as the rotors 201 and 202 rotate, the compression chamber 50
0 volume decreases and compresses the refrigerant. Compression chamber 500
A discharge hole is opened at the position where the volume of the refrigerant is the smallest, and high-pressure refrigerant is discharged into the discharge chamber 363 through this discharge hole.

Therefore, since the female rotor 201 has six grooved grooves 205 and the male rotor 202 has four protrusions 204, the rotation of the shaft 352 is accelerated and the male rotor 20
2 will be transmitted.

In the above-mentioned operating state, as shown in FIG.
04 tip and the tip of the female rotor. Here, since the tip A2 of the female rotor has an arc shape having a radius substantially the same as the radius R+ of the first cylinder chamber 101, a sufficient seal can be ensured at the tip of the female rotor 201.

Further, a circular arc portion A1 is also formed at the tip of the male rotor 202, and the circular arc portion corresponds to the radius R0 of the second cylinder chamber 102.
Since the radius is almost the same as that of the male rotor 202, the second
Surface contact can be made with the inner surface of the cylinder chamber. Therefore, according to the compressor of this example, a good seal is maintained between the compression chamber during compression and the compression chamber during suction, improving compression performance.

Here, the reason why the angle α of the circular arc portion A1 at the tip of the male rotor 202 is set to about 5@ in this example is as follows.

If this angle α is too small, the area of the arcuate portion A1 will also be small, and therefore a sufficient sealing performance with the inner wall of the second cylinder 102 cannot be achieved.

On the other hand, if the angle α becomes larger, the curve 10-11 of the circular arc portion
The length of will increase. In other words, point 10 will deviate more than point 11. And the curve 31-36 of the female rotor 201 is at point 10.
Since it is a cycloid curve created by the rotation of
If point 10 deviates more than point 11, the bend in curves 31-36 will increase. In other words, as shown in FIG. 3, the curve 31- of the female rotor 201
36, the arc 10-11 of the male rotor 202, and the curve 10-
17 becomes large. Here, if such a gap remains between the male rotor 202 and the female rotor 201, it will become a dead space in the compression chamber 500 and deteriorate the compression performance. Therefore, if the angle α becomes too large, the sealing effect that can be secured by the circular arc portion A will be lost, but the negative effect of the dead space will become greater. Therefore, in this example, the angle α is set to 5°.
It is said that the amount of According to studies by the present inventors, it is practically possible to use an angle α of about 2″ to about 8°.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view showing an embodiment of the compressor of the present invention, FIG. 2 is a cross-sectional view of the compressor shown in FIG. 1, taken along line A-A, and FIG. 3 is a rotor section of the compressor shown in FIG. It is an explanatory view showing tooth profile shape. 201...Female rotor, 202...Whose rotor, 300
... Housing, 101 ... First cylinder, 102
...Second cylinder, 352...Shaft.

Claims (1)

[Claims] a housing having a first cylindrical cylinder chamber with a radius R_1 and a second cylindrical cylinder chamber with a radius R_0;
a female rotor rotatably disposed within the cylinder chamber and having an outer diameter slightly smaller than the radius of the first cylinder chamber; and a female rotor rotatably disposed within the second cylinder chamber and having an outer diameter R_0 of the second cylinder chamber radius. a male rotor that is slightly smaller and has a pitch circle radius that is the same as the pitch circle radius of the female rotor;
a shaft that is connected to either the male rotor or the female rotor and transmits rotational force to the male rotor or the female rotor, and the second housing chamber extends over a predetermined angle at the tip of the protrusion of the male rotor. A circular arc portion having a radius R that is slightly smaller than the radius R_0 is formed, and the concave portion of the female rotor has a curved portion that is a cycloid curve created by the end of the circular arc portion of the male rotor. screw compressor.